Clamp to secure an abrasive segment on a rotary chuck



June 18, 1957 E A. s. TITCOMB CLAMP TO SECURE AN ABRASIVE SEGMENT ON AROTARY CHUCK Filed 001:. '24, 1955 v INVENTOR- A. 5HEPARD 77TcoMa BY QQMfi' ATTORNEY United States Ettent 9 CLAMP T SECURE AW ABRASIVE SEGMENTON A ROTARY CHUCK Albert Shepard Titcomb, Hamden, Conn.

Application October 24, 1955, Serial No. 542,216

6 Claims. (Cl. 51-209) This invention relates to an abrasive chucck, andmore particularly to an abrasive segment holder which will adjustablysecure the segment on a rotary plate.

In accordance with my prior Patent #2,54.l,844. of

February 13, 1951, I have provided a chuck in which a plurality ofabrasive segments are supported in plowlike positions on a rotary plateso that the abrasive detritus may be moved outwardly and away from thezone of grinding as the segments are revolved. In that construction, anadjustable plate is provided which serves to hold the segment in one ofseveral positions so that as the segment is worn away during usage itmay be moved outwardly to provide more abrasive material for thegrinding operation. The abrasive block is supported only by a cornerengagement with a narrow ledge on an adjustable plate, and this supportdepends upon a screw threaded adjustment for properly positioning theplate to hold the segment.

The primary object of my invention is to provide a simpler and lessexpensive construction which will serve to hold an abrasive segment inone of two adjusted positions and which provides an extensive surfacerigidly held in engagement with the segment in its outwardly adjustedposition to prevent any accidental displacement thereof.

A further object is to provide a movable support which may be moved outof the way so that a segment may be mounted in the clamping holder inits initial position, or it may be moved outwardly to aposition where itsupports a medial portion of the segment and is itself rigidly supportedby the rotary plate. Further objects will be apparent in the followingdisclosure.

Referring to the drawings illustrating a preferred. embodiment of theinvention:

Fig. 1 is a top plan view of a grinding chuck having three abrasivesegments mounted therein in their secondary outwardly adjustedpositions, the rotary supporting plate being indicated by dotted lines;

Fig. 2 is a perspective view of one of the individual abrasive holdersshowing particularly the inside of the holder and the adjustment platein its abrasive supporting position;

Fig. 3 is an elevation of the outside of the holder and a portion of themounting plate and 'a segment, shown bottom side up;

Fig. 4 is a top plan view of the abrasive block clamping unit with theadjustment plate shown by dotted lines in a secondary position; and

Fig. 5 is a fragmentary detail showing the lock for holding the abrasivesupporting arm in position.

In the embodiment illustrated, the segment clamping unit comprises anarcuate metal body and an adjustable clamping jaw 11 which, as indicatedin Fig. l, form a segment holder arranged to be mounted on a rotaryplate 12, which is suitably mounted on a power driven spindle, usuallyarranged either horizontally or vertica-lly for rotating the abrasivesegments in. an operative contact with the work piece supportedthereagainst.

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The body 10 has a fixed lip Iii-shaped to interfit with the trailing:end of the abrasive segment 14, and the adjustable. hook-shaped jaw 11interfits with the leading end of the abrasive segment. The holder 10 isso mounted on the plate as to. impart the required revolving motion to;the segment, as. well as to support it for a plow-like action on thework, as explained in said patent. The inner arcuate face 1510f thesegment holder unit is comprised of suitable land surfaces shaped tointerfit with certain outer surfaces of the convex face of the abrasivesegment, suitable pads being interposed between the abrasive segment andthe metal walls of the holder to obviatje breakage, of the segment bythe clamping pressure. The inner face of the segment is not supportedexcept at the trailing end by the fixed lip and on the leading end bythe adjustable jaw.

The, wedge-shaped leading; edge portion or plow-like nose of theabrasive segment is supported by and clamped inplace by. means of theadjustable jaw 11 which interfits therewith. This jaw is V shaped andcomprises a rear portion 18 slidably interfitting in a socket 20 in theouter face of the clamp. body 10; That rear wall 18 of the adjustablejaw 11 is internally threaded lengthwise to receive a set screw 22 whichpasses freely through an outwardly projecting lug 23 (Fig. 1) "formed by'a recess on the outside of the body- 10. The, enlarged head of thescrew 22 has a recessed hexagonal socket or other suitable constructionfor receiving a wrench or screw driver which. serves to draw the noseplate 18 portion ofthe movable clamping jaw rearwardly to clamp theabrasive segment firmly in place in the holder. The adjustable jaw 11does not extend the full height of the metal holder 10 but only abouttwo thirds of the way.

Its lower edge portion lies in the plane of the bottom of the arcuatebody 10 sothatit'will clamp fully against an. "abrasive block which hasbeen moved outwardly to its. finally adjusted position. The body 10 isprovided with suitable threaded holes 25 near its two ends whereby theblock may besuitably seured to the rotary plate 12, as is described inmy prior patent. Other constructional details shown in that patent maybe incorporated in this device as it is modified to embody the presentinvention.

The primary feature of this invention resides in the movable plate orstop 30 which is so mounted that it may be moved from an inoperativeposition to one of extensively engaging the upper face of the abrasivesegment and holding it in a lower adjusted position. This stop- 30. ispreferably a swinging arm pivotally mounted on a vertical pivot pin 31positioned in aligned holes 32; arranged in the upper and lower rib-likeportions of the clamp body 33 (Fig. 2). formed by casting a central holein the supporting clamp body 10. The arm 30 has an enlarged hinge lug 34located in the central elongated hole between the ribs and provided witha pivot hole adapted to. carry the pivot pin. 31 for its swingingadjustment. The swinging arm 30,. in its inoperative positionrests. in-arecess 35 formed in the inside of the wall 10,

which has. such shape and dimensions that the arm 30:

will lie out of the way. of the convex outer face of the abrasivesegment, or so that the concave inner wall of theswinging arm will beflush withthe inner arcuate face 15 of the body 10,. This permits theabrasive segment to be positioned initially in the. holder withoutinterference from the swinging arm, It will be noted that the surface ofthe innerportion of the body 10 below the recess 35 forms. substantially'a continuation of the arcuate surface 15 at the ends. of the body 10-and thus. provides. strength. in this lower area, the abrasive blockbeing securely held in the end land portions. That is, a newa'brasi-veblock is mounted with its upper face substantially flush; with the topface of the holder and contacting with the under face of the rotaryplate 12 and its lower operative portion projects out from the holder19.

The swinging arm 30 is provided with outwardly projecting locating lugs42 which project into larger holes 43 in the side of the holder 10.These lugs are flush with the lower edge of the swinging arm 30 and formwide under surfaces for engaging the abrasive block. The inside of thelip 13 is provided with a slight recess 45 so positioned that when thearm is swung outwardly to the position of Fig. 2, its free end locksreleasably in that recess as permitted by a loose pivot and helps tohold the arm positioned. This locking movement may be readily aided by atapered lock pin 44 removably inserted in aligned grooves in the body 10and lug 34 which hold the end of the swinging arm rigidly in the recess45. The pin is mounted in a hole 46 in the body 10 and its lower taperedend engages a wedging face 47 of a slot milled in the outside of lug34'.

When new segments are mounted in the chuck, the arm 34) (Fig. 4) islocated entirely out of the way. After the abrasive has worn down tosubstantially the lower face of the chuck, the clamping jaw 11, 18 isreleased from its clamping engagement with the forward nose of thesegment, and the latter moved to a position which permits the arm 30 tobe swung outwardly into the position shown in Fig. 2 and indicated indotted outlines in Figs. 1 and 4. The segment is then positioned withits top face in contact with the lower edge portion of the arm,including the lugs 42, and the clamping jaw 11, 13 is then drawn intoplace to thrust the trailing portion of the segment into the V-shapedsocket formed by the fixed lip 13. Since all of the arms 30 of thevarious segment holding blocks are similarly positioned, then theoperative faces of the segments are automatically brought into the sameplane, and when the clamping jaws are set, the chuck with its segmentsis then ready for renewed use. The drawing force of the jaw 11, 18 isrequired primarily adjacent that portion of the segment which is belowthe swinging arm 30. Hence, it is feasible to have the clamping jaw part18 recessed into the end of the arcuate body 10 as shown at 20 in Fig.1.

The arm 39 is supported only at its pivoted end, but its upper face liesin a plane and is adapted to contact fully with the under face of therotary mounting plate 12 so that the upward thrust of the abrasiveaction against the segment is fully absorbed in that upper plate. Theselugs have a further purpose, however, in that these lugs project throughthe holes in the side of the clamp body it), they automatically aid infreeing the holes from any accumulation of detritus formed by thedisruption of the abrasive segment and removal of fragments from thework. Thus, lugs 42 have a primary purpose in that they are located atthe extreme bottom edge and in line with its surface so that they form awider supporting surface in engagement with the segment.

This construction differs from that of my prior patent in that it ismuch simpler in design and cheaper to manufacture and involves the lossof less time in the adjustment of the abrasive segment. In particular,the swinging arm 30 engages the segment throughout a considerableportion of its length and thus supports the segment medially between itsleading plow point and trailing end which are clamped within theV-shaped sockets formed at either end of the clamp body by the movablejaw 11, 18 and the fixed lip 13, respectively. That is, the V socketstend to hold the ends of the segment in place and the swinging armsupports the intermediate portion against the upward pressure of thegrinding action. That is, the arm extends transversely across the medianline between the two sides of the segments which is substantially thecenter of pressure and thus provides a balanced support for the segment.

The pivot support for the arm or abutment gate 30 is near the leadingend of the segment holder, so that any swarf or residue which is sweptinto contact therewith tends to be thrown inwardly away from the segmentand to a position where it may ultimately escape between the adjacentsegment bodies when the rotary plate is rotated in the direction of thearrow in Fig. 1. In other words, this abutment gate 30 acts as a coolantguide. As explained in my prior patent, the forward nose of the segmentis located radially inwardly of the trailing portion or end, and thesegments are spaced apart and so arranged that the detritus will escapefrom the .inner side or edge of the segment that has ground it off ofthe stock and escape outwardly between two of the segment bodies beingploughed outwardly by the outer side of the succeeding segment, and thusbe removed from the working zone. Hence, this gate 30 tends to sweep theresidue away from the space above the segment within the clamp body.

Another advantage in this construction, as indicated particularly inFig. 2, is that the arcuate body 10 has thick walled ends which areadequate for receiving large screws in the holes 25 so as to resistfully the centrifugal force of high speed revolution of the rotary plate12. The body 19 is accordingly made thick at locations required forresisting the forces which would tend to cut off the screws interfittedin the holes 25. This is recognized as an improvement over our formerconstruction, and is covered hereby.

In this grinding chuck the segment holders are open ended and soconstructed that the abrasive segments may project close to or bearagainst the under side of the face 12 of the rotary plate during theinitial grinding operation and thereafter may be supported by themovable arm 30 in an outwardly adjusted position. The arm 30 is solocated that it engages the segment medially, in that it contacts withthe segment between its forward and rear points or ends, and preferablyit extends transversely across the segment somewhat near a central pointso as to provide maximum lateral and longitudinal support adjacent thecenter of pressure. Also, this movably mounted segment support may beassociated with various types of clamp made in accordance with standardconstructions as well as that shown in my prior Patents No. 2,541,844and No. 2,700,853. This movable arm may lie in a coextensive recess inthe wall 10 and substantially in an inoperative position laterally ofthe segment, although the segment may or may not bear against and bepartially supported by the inner curved face of the arm. In theconstruction shown, that inner face of the support 30 is nearlycoextensive with the recess 35 and it forms substantially a continuationof the curved surface 15 of the holder. This can give a supplementarylateral support for the segment when first mounted. Although theswinging arm may be rigidly mounted on the body 10, it is desirable thatits upper face or edge contact with the inside face of the rotary plate12 so as to provide a rigid support for the segment.

The arm 30 is held in the outward position shown in Fig. 2 by means ofthe locking pin 44 which has a lower wedge shaped portion, as shown inFig. 5, which engages the tapered face 47 of the slot milled in theouter circular portion of the lug 34 of the arm. In normal use theholder and abrasive are reversed from the position shown in Fig. 3 sothat the pin is vertical and gravity tends to hold the wedge down inplace. Various other modifications may be employed to lock this swingingarm in its outwardrnost position so as to provide an immovable rigidsupport for the top face of the abrasive segment.

Other modifications may be made in this construction, and the abovedescription is to be construed as setting forth the principles of theinvention and a preferred embodiment thereof and not as imposinglimitations on the appended claims.

Ielaim:

1, An abrasive segment holder comprising a hollow body having a sidewall, a fixed V-shaped end hook for engaging one end of the segment andan adjustably mounted V-shaped hook for clamping the segment against thefixed hook with its outer abrading face projecting outwardly beyond theside wall, a movable segment support having an outer face capable ofextending across the segment between its sides, and means for movablymounting the support on the holder body so that the support may movefrom a lateral non-supporting position to one where said outer faceextends across and in contact with an extensive transverse portion ofthe inner face of the segment, said support having its segment engagingface remote from the plane of the outer edge of the side wall andbetween the hooks so that it may support the segment in an outwardlyadjusted position while the segment is clamped between said hooks.

2. A grinding chuck comprising a rotary plate having an inner face, anabrasive segment holder secured against said face, said holder having aside wall and two opposed relatively adjustable hooks arranged forclamping the segment therebetween in one of two positions where itsinner face is close to or alternatively is remote from said plate face,a segment support having an outer face shaped to engage an extensiveportion of the segment transversely across its median line, and a pivotfor the support mounted on the side wall, said support being movablefrom a position laterally of the segment to one where its inner edgeengages said plate face and said outer face extends across and supportsthe segment in balance in a projected position.

3. A grinding chuck comprising a rotary plate having an inside face anda segment holder removably mounted on the plate, said holder having arecessed side wall and two opposed relatively adjustable members forclamping a segment therebetween, an arm pivoted on the holder andmovable from a position within the recess laterally of the segment toone where it extends across the inner face of the segment and supportsthe latter in an outwardly adjusted position, said recess and arm beingextensive so that the arm may extend fully across the segment, and thearm being shaped and arranged to contact at its opposite edges with thesegment and said plate face so that the segment is rigidly supportedagainst the grinding thrust.

4. A chuck according to claim 3 in which the holder side wall hasopenings therethrough and the pivoted arm has lugs projecting into theopenings when located in the recess, the openings being larger than thelugs and aiding in removing the abrasive detritus.

5. A chuck according to claim 3 in which the segment holder and the armhave recesses that arealigned when the arm is in a segment supportingposition and comprising a removable lock insertable in said alignedrecesses to hold the arm rigidly in place.

6. A grinding chuck comprising a rotary plate having an inner face, anabrasive segment holder secured against said face, said holder having aside wall and two opposed relatively adjustable hooks arranged forclamping the noses of a segment therebetween in one of two positionswhere its inner face is close to or alternatively is remote from saidplate face, a support having an outer face engageable with the segmentinner face, and a pivot for said support mounted on the side wall nearthe forward nose of the segment, said support being movable from anon-supporting position laterally of the segment to one where its inneredge engages the rotary plate and said outer face extends obliquely andrearwardly towards the trailing end portion across and in supportingcontact with the segment, so as to aid in keeping the inner surfaces ofthe holder free of detritus during the grinding operation.

References Cited in the file of this patent UNITED STATES PATENTS2,541,844 Titcomb Feb. 13, 1951

